Ring gear and method of making the same



Patented June 21, 1927.

FRANK J. BLACIQ OF CBAFTON, SYLVANIA.

i RING Gm AND METEOD OF MAKING THE SAME.

Application med :une 27, 1922. Serial No. 571259.

This invention relates to gears and more particularly to ring gears and the method of manufacturing the same, and has for one of its objects the provision' of a ear of this class that will be more durable, e cient,

and less noisy in operation than gears heretofore made. i

Another object is the provision of a gear of this class and method of making same having the novel features hereinafter described and illustrated in the accompanying drawngs.

Heretofore' ring gears have been formed from rolled steel slabs by forging the slabs into blanks substantially as shown in Figure 5 and then cutting teeth therein. The flow lines or grain of the metal of the rolled slabs necessarily extend or run lengthwise of theslab and, therefore, when a circular gear blank is formed fromsuch slabs the flow lines or grain of the metal on two quarters of the blank run parallel with the cut of the teeth, thereby materially weakening the teeth .in that area. Experience has shown that 99 'per centof the breaking out of the teeth on ring gears occurs in this area. Also ring %ears formed from rolled steel slabs do not ave uniform shrinkage when heat treated to harden them. Experience has shown that where the flow lines runnin parallel with the teeth in two quarters of t e rin connect with the other two. quarters, the s inkage varies from .003 to .004 inches thus producing a very noisy and often defective gear.

The present invention entirely overcomes these difiiculties and provides a. gear in which the flow lines or ain of the metal extends perpendicular with the cut of the teeth at all points on the g'ear.

*Referring to t e drawings, Figure 1 is an elevation of a rolled steel round used'in carrying .o'ut the method of this application.

Fi e 2 is a sectional elevation of the pierced blank formed from the round' of Figure Figure 3 is a sectional elevation of the drawn tubular blank formed from the -pierced blank of Figure 2.

Figure 4 is a sectional elevation of a ring ar blank cut from the tubular blank of i re 3. 1

igure` 5 is asectional' elevation of the gear blank of Figure 4 after forging. 66 igure 6 is a sectonal elevation of the i eliminatin ring gear blank of Figure 5 after the teeth have been cut thereon. r

In carryin out this invention ingots are first rolled own to produce long rounds which are then sheared or otherwise cut to short lengths to form the blank rounds or cheeses 2 shown in Figure 1. The blank rounds 2 are then pierced lengthwise by any and when said rounds are tgierced the pieroing plug or tool will force e impurities and poor metal forward into the head or closed end 4 of the pierced'blank 3,' which head is cut from the blanks and scrapped, therefore this poor metal and impuri-ties from the' rng blanks.

The ierced blank 3 is further elongated, thinned: and worked by drawing itvon a mandrel after the fashion 'of drawing seamless tubes or 'the like, to produce the tublar drawn' blank 5 of Figure 3. The blank 5 is then cut into short lengths to form the ring blanks 6 of Figure 4, which are substantially the size of the finished gear.

The ring blanks 6 are, then heated and forged to produce the forged ring blank 7 of Figure 5, which isthe same shape and size as the finished gear. *The blanks 7 are then milled or otherwise cut to form the teeth 8 on their one side face as shown in Figure 6.

It will be noted that all working of the rnetal in producing the blanks from the rollng of the ingot to form 'the rounds to the drawin operation used' in producing the thin tu ular blank 5 of Figure 3 is iengthwise of the longitudnal 'axis of the blanks and therefore the flow lines or grain of the metal necessarily extend orrunparallel to the longitudinal axis and perpendicular to the cut of the teeth 8 around the entire gear.

After the blanks 7 have had the 'teeth 8 cut therein they are heat treated to har-den f them and finally ground to produce perfect finish required on such gears; a

The primary novel feature of this inven tion lies in producing 'a ring gear in which the flow lines or 'grain of the metal runs steps comprising forming a tubular blank by piercing and drawing, cutting 'ings 'from said blank, and forming teeth on at least one side face of said rings.

2. In the manufacture of ring gears the steps comprising forming a tubular blank by percing and drawing, cutting rings from said blank, and forging said ring to -form, and cutting teeth on at least .one side .face thereof.`

3. In the manufaeture of ring ears the steps comp'ising fo-ming a` rol ed steel round, piereing and drawing said round to form a tubular blank, cuttin i rings from said blank, and forming teet one side face of said rings.

4; A ring gear formed from a drawn steel.

blank and in which the flow lines or grain lar to the cut of all the teeth.

5. In the manufacture of ring ears, the steps' com rising forming a circu ar blank having th' 'grain of the metal running in a line' substantially parallel to the axis there- :face of said blank se that the grain of the metal 'will 'extendj substantially perpendieu- -lar to the eut of the teeth.

6. A ring gear having the flo'w lines or grain of the metal running substantially perpendicular" to the cut of all the teeth.

In testimony 'whereof I have hereunto set my hand.

, v FRANK J. BLACK.

on at least ofthe metal runs substantially perpendicuof, and formingteeth on at least one side' 

